1. Field of the Invention
There exist many optically active substances in pharmaceuticals, but they are often used in a form of (.+-.)-racemates. However, it is known that one enantiomer is sometimes quite different from the other in activity or toxicity or in metabolism and, therefore, it is necessary to evaluate each enantiomer individually. This invention relates to compounds suitable especially for microanalysis of optical isomers of carboxylic acids among optically active compounds, and to fluorescent chiral derivatization reagents containing said compound.
2. Prior Art
As for fluorescent chiral derivatization reagents that are capable of analyzing optically active carboxylic acids with high sensitivity, hitherto there have been only the following three kinds: Goto et al. analyzed N-acetylamino acids and .alpha.-allyl propionic acids by normal-phase high performance liquid chromatography (HPLC) with the use of 1-(4-dimethylamino-1-naphthyl)ethylamine (J. Goto et al.: Anal. Chim. Acta, 120, 187 (1980)). In addition, as a reagent 10 times as sensitive as the aforesaid reagent, they disclosed 1-(1- or 2-anthryl)ethylamine (J. Goto et al.: J. Liq. Chromatogr., 9, 683 (1986)).
However, even with 1-(1 or 2-anthryl)ethylamine, the detection limit is 100 fmol, which is still not necessarily sensitive enough. Thus, it has not been used in the reverse-phase HPLC, which is more advantageous than the normal-phase HPLC in analysis of samples taken from living bodies.